Moon and Antares

StarDate: July 3, 2009

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The night sky of a thousand years from now -- or 2,000, or 3,000 -- won't look much different from what you see tonight. The stars will look the same, and they'll form the same constellations, too.

But it's possible that one or two of the stars that are visible to the unaided eye won't be around any more. In fact, they may have died already, but we just haven't received the news.

One such star is Antares, the bright orange "heart" of the scorpion. It's a little to the lower left of the Moon as darkness falls tonight.

Antares is a supergiant. It's far more massive than the Sun, so it's burning through its nuclear fuel in a hurry. When the fuel's all gone, the star most likely will explode as a supernova. For a while, it'll outshine everything else in the night sky except the Moon. After that, it'll fade away, leaving the scorpion without a heart.

It's even possible that Antares has already exploded. It's about 600 light-years away, so we see the star as it looked about 600 years ago. So if Antares has exploded during the last six centuries, the message is still on the way.

Whenever Antares explodes, Earth won't see it until six centuries later -- a bright "time capsule" of light from a distant star.

For now, watch Antares as it follows the Moon across the south tonight. The Moon actually creeps closer to Antares as the night goes on, so they'll be closest together as they set in the wee hours of the morning.

Script by Damond Benningfield, Copyright 2009

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